Continuing investigations will be concerned with: (1) further investigation on the sequential distribution of cytoplasmic actin and myosin with indirect immunofluorescent techniques in nonmuscle cells of the developing palatal shelf. Specifically, we will be interested in obtaining an accurate impression on the intensity of the immunofluorescent reaction during and subsequent to palatal shelf rotation. (2) in vitro studies investigating the effects of smooth muscle contracting agents, plus the effects of complement and the prostaglandins on epithelial and mesenchymal cells of excised palatal shelfs.